For hydronic emitters (including radiators, underfloor heating/cooling circuits, fan coils, chilled beams) the rate at which the water flows through the emitters need to be regulated to ensure all circuits/emitters in an environmentally temperature controlled system are balanced. The water flow varies due to different distances, connection circuitry and size of the pipes from the water pressure source or water pump. In order to make the system work in balance, a mechanical or fixed flow restricting valve may be employed in the inlet and/or outlet of each hydronic emitter to allow it to regulate the flow rate of each emitter in order to maintain a balanced flow of the water to each emitter throughout the system.
This process of balancing an environmental temperature control system is often quite tedious and may require numerous iterations in order to fine tune a balanced system. The time required to balance a system may be extremely long with a more complicated configuration.